A fiber optic cable is a glass or plastic fiber designed to guide light down its length by total internal reflection. Fiber optic cables are used in fiber-optic communication which permits digital data transmission over longer distances and at higher data rates than electronic communication.
The total internal reflection phenomenon, which occurs when light travels down a fiber optic core of a fiber optic cable, requires that the light rays reflecting off the boundary of the fiber optic core not exceed a critical angle of reflection at the boundary. This critical angle of reflection is determined by a ratio of indices of refraction of the fiber optic core and the cladding which surrounds the core and is made from a substance with an index of refraction greater than that of the core. To avoid letting the reflection angle exceed the critical angle, fiber optic cables should not curve at an angle sharper than a specified bend radius for the given fiber optic cable.
Fiber optic cables may be connected to each other by splicing, or joining two fibers together to form a continuous optical waveguide. In the field, technicians typically perform a mechanical splice whereby the fiber ends are aligned and held together with a sleeve often using a gel that enhances the transmission of light across the joint. A splice block is a device used for mechanically splicing two or more fiber optic cables together. A splice block is typically housed in an enclosure to protect the spliced fiber optic cable.